Theory of helicity-sensitive terahertz radiation detection by field effect transistors

TL;DR

This paper develops a theoretical model explaining how field effect transistors detect the helicity of terahertz radiation through antenna-induced signal mixing, highlighting dependencies on device parameters.

Contribution

It introduces a comprehensive theory based on the two antenna model to explain helicity-sensitive detection in FETs, including quantitative predictions.

Findings

Helicity-sensitive photoresponse depends on antenna impedance.

The response varies with gate length and voltage.

The theory matches experimental observations.

Abstract

Within the two antenna model, we develop a theory of the recently observed helicity-sensitive detection of terahertz radiation by FETs. The effect arises because of the mixing of the ac signals produced in the channel by the two antennas. We calculate the helicity-dependent part of the photoresponse and its dependence on the antenna impedance, gate length, and gate voltage.